Rolling bearing assembly and wind turbine equipped therewith

ABSTRACT

A rolling bearing arrangement comprising two rings arranged concentrically and at least regionally one inside the other, and a gap between the rings, such that the rings are rotatable in opposite directions about an axis at the center of the rings and perpendicular to a ring plane, wherein at least one raceway is closed on itself in a circular shape in a plane and is provided with at least one row of symmetrical rolling bodies between the rings, wherein the rolling bodies of one row are guided at generally equidistant spacings by a cage having at least one disk-shaped region is placed in continuously circumferential, groove-shaped depression in the region of the raceway of one bearing ring, and wherein the cage is shaped like a comb, comprising a plurality of spacers that are joined together along a spine region, and, between every two neighboring spacers, a respective pocket for receiving a respective rolling body.

The invention is directed to a rolling bearing arrangement, particularlyin the context of a (drivable) rotary joint, preferably for a main,blade and/or nacelle bearing of a wind turbine, comprising two annularconnecting elements arranged concentrically to each other and at leastregionally one inside the other, and comprising a gap between saidconnecting elements, such that the latter are rotatable in oppositedirections about an imaginary axis at the center of the connectingelements and approximately perpendicular to the ring plane, wherein atleast one raceway that is closed on itself in a circular shape in aplane and is provided for at least one row of rotationally symmetricalrolling bodies rolling between the connecting elements is disposedbetween the connecting elements in the region of a gap portionsurrounding the axis of rotation at an approximately constant radius,wherein the rolling bodies of one row are guided at approximately equalspacings by a cage having at least one approximately disk-shaped regionthat is placed in a continuously circumferential, groove-shapeddepression in the region of the raceway of one connecting element, andwherein the cage is shaped like a comb, comprising a plurality ofspacers that are joined together by simple connection along a spineregion, and, between every two neighboring spacers, a respective pocketfor receiving a respective, preferably spherical, rolling body, whereinthe opening of a pocket extends continuously in the top face of thecage, over the opposite edge thereof from the spine region and on intothe bottom face thereof; the invention is further directed to a windturbine equipped with at least one such rolling bearing.

Rolling bearings, or rotary joints provided with rolling bearings—someof these being drivable joints—have applications in a great many areas.Large rolling bearings, for example with a raceway diameter of 1000 mmor more, are used, inter alia, in wind turbines, preferably in windturbines having a wind wheel with one or more vanes and an axis ofrotation that is pitched roughly parallel to the wind direction duringoperation. Such large rolling bearings are relied on in particular tosupport the blades and the nacelle as a whole, but also to serve as themain bearing or rotor bearing supporting the hub of a wind turbine; withsuitable dimensioning, they can absorb all the axial and radial forcesand tilting moments that occur. In many such applications, for examplein the case of blade bearings, preloaded, i.e. play-free, raceways areused. One advantage of this is improved load distribution in the racewaysystem, and thus improved service life. A frequent choice here is afour-point type of bearing, i.e., a bearing with spherical rollingbodies and two raceways shaped so that each ball has two contact pointswith each raceway. Such bearings are easy to preload. However,particularly in the case of such four-point bearings, combined loads inthe raceway system (axial and radial forces and tilting moments) cancause different contact angles to develop between a ball and a raceway;moreover, depending on the load combination and the position of a givenindividual rolling body, four-point contact may even give way totwo-point contact. Such displacement of the contact points of individualrolling bodies can alter their positions relative to adjacent balls;consequently, to prevent the balls from becoming unevenly distributed, acage is often inserted to maintain consistent ball spacing. A cage doescall for a larger gap width than a cageless rolling bearing does, sincethe connection between the spacers of the cage must not be below acertain minimum thickness for reasons of stability. This reduces theachievable load-carrying capacity, since the contact area of a rollingbody approaches the edge of a raceway more often and at greater speeds.

It has already been proposed, therefore—for example in DE 33 00 655A1—to provide in the region of a raceway a dedicated groove in which areguided individual cage segments each of which has, for example, twopockets for receiving a respective a rolling body, such that, despitethe use of a cage, the width of the gap between the two annularconnecting elements need not be increased compared to an embodiment thathas mutually separated intermediate pieces instead of a cage. Adisadvantage, however, is that here, instead of a single cage, it isnecessary to use a large number of small cage segments with only tworeceiving pockets apiece for rolling bodies, with the result thatassembly becomes very onerous precisely in the case of large rollingbearings with diameters on the order of approximately 1000 mm or more.What is more, cage segments that are only loosely juxtaposed can createadditional problems in preloaded bearings, since under the substantialforces acting on a large rolling bearing during operation, for examplein a wind turbine, the individual cage segments can shift despite bestefforts, as a result of which individual rolling bodies can jam and thussuffer increased wear.

From the disadvantages of the described prior art comes the probleminitiating the invention, i.e., so to refine a cage-equipped rollingbearing arrangement of the aforementioned species that the assembly ofthe cage is as simple as possible; a further aim is to ensure that allthe rolling bodies are maintained at the applicable uniform spacingwithout becoming jammed.

This problem is solved by the fact that the cage is completelyinterrupted in at least one location and is formed from a spring-elasticmaterial, such that it can be elastically bent open and/or closed in thearea, particularly the plane, of the approximately disk-shaped region.

A cage is preferably interrupted only once, and therefore, as a whole,is of one piece or simply connected. It is also possible, however—as maybe the case with particularly large rolling bearings—to divide the cagetwo or three times, but, insofar as possible, no more than for examplefive times, preferably no more than four times, particularly no morethan three times. The spring-elastic material is capable of changing itsbending radius so that it can be placed in a groove optimally and withminimal effort, for which purpose it first must be forcibly deformed inorder to be slipped past the end face of an annular connecting elementto the raceway of the latter; once in the groove provided for it, thecage relaxes again, rebounding toward its original shape.

It has proven advantageous for the cage to consist of a metal, forexample steel, preferably spring steel or quenched and tempered steel.Such a material particularly has a high compressive strength, so that itcan withstand the high forces inside a rolling bearing.

Preferably, four, more or all of the spacers of the cage are connectedto one another, such that three, more or all of the pockets eachprovided to receive a respective rolling body are connected to oneanother. Since displacements in the bearing are most likely to be causedby abutment locations between unconnected cage segments, these should beavoided insofar as possible.

The cage should be fashioned in such a way that should the distancebetween the end faces of two neighboring spacers change, their end facesdo not deform, in particular their top and bottom edges do not shift inrelation to each other. This is the only way to ensure that the rollingbodies will not jam even if the ring deforms, for example as a result ofthermal expansion.

A preferred measure for obtaining high shear strength inside the cage isto make it from only one layer of material. At worst, macroscopicdeformation of the material itself could cause jamming, but this ishighly unlikely, especially if the cage is made of metal.

It is within the scope of the invention that at least one spacer has agreater height than the spine region of the cage. This makes it possibleto surround a ball over a large area; the ball can thus be constantlyforced into the particular desired position with very low surfacepressure, hence extremely gently and with the utmost freedom from wear.

All the pockets of the cage should be open on the opposite longitudinalside of the cage from the spine region. On the one hand, this gives thecage good flexibility, since the pockets can open or tighten, asrequired; on the other hand, in this way all the pockets can be filledwith rolling bodies from the same side or raceway, i.e., through one andthe same fill opening.

According to the invention, the cage has at least one designated bendingarea, preferably in its spine region. This can preferably be a narrowingof the cross section of the cage, where its resistance to bending islower, due to the more or less homogeneous properties of the cagematerial.

At least one designated bending area preferably extends transversely tothe circumferential direction of the rolling bearing, for instancefollowing a line of smallest cross section through it.

At least one such designated bending area can be provided in the regionof a (or each) spacer, since the spacers are located between twoadjacent rolling bodies, and thus any deformation in this area, forexample as a result of hyperextension during assembly, will not cause arolling body to become jammed.

The invention recommends configuring at least one designated bendingarea as a notch in the cage, particularly in the end face of the spineregion. The cage is thereby intentionally given lines of weakness whereit can deform under excessive loading without any adverse effect on itsability to function.

The maximum depth of at least one notch should approximately correspondto the minimum width of the spine region at the base of a pocket. Thespine region can be completely interrupted at the notch locations, suchthat the cage is held together only by the spacers at those locations.This gives the cage very high flexibility in the region of the spacers.It should be noted that the spacers are not very deformable at all intheir central vertical plane or plane of symmetry, but rather, rightnext to it*, i.e., approximately in or at the foot region of the twoflanks of a spacer.

In addition, a notch should pass all the way through the spine region ofthe cage from its top face to its bottom face, so that the cage isuniformly flexible over the entire cross section of the spine and localoverstrains are prevented.

It is within the scope of the invention that at least one notch hasrounded edges, preferably at the edges extending vertically relative tothe base of the rolling bearing, particularly in the region of thetransition between the flanks of the notch, i.e. at the base of thenotch, and/or beyond its two flanks, i.e., at the transition into theadjacent spine region.

The rolling bodies are preferably embraced by the cage where theirperipheral speed is highest as they roll, i.e., preferably approximatelyin the region of their equator. Particularly in an embodiment of thiskind, the groove that guidingly receives the spine of the cage islocated approximately centrally in the raceway of the connecting ringconcerned, i.e., approximately at half the height of the raceway. Suchan arrangement has the advantage that the rolling bodies are embraced ontheir plane of symmetry and therefore do not exchange radial forces withthe cage, which thus experiences no bending moment transversely to itslongitudinal direction.

It is sufficient if the rolling bodies are embraced over no more than270° of their circumference, for example only over 230° of theircircumference or less, preferably only over 190° or less, particularlyonly over approximately 180° of their circumference. The spacingelements of the cage should not be too long, since their free ends movethe most during bending, so the spacing between these ends can changeconsiderably. In particular, inelastic deformation of individualportions of the cage—during assembly, for example—could therefore causeindividual rolling bodies to jam. This can be prevented if the length ofthe spacers approximately perpendicular to the cage spine, i.e., in theradial direction relative to the axis of rotation of a radial bearing,is equal to approximately only the (maximum) radius of a rolling body,i.e., the rolling bodies are embraced only over two diametricallyopposite surface regions.

If—as the invention further provides—the inner face of at least onepocket for receiving a respective rolling body is at least regionallygiven a concave curvature parallel to the plane of the rolling bearing,approximately at the level of the spine region of the cage, then such ahollow curvature can be optimally adapted to the convex surfacecurvature of a rolling body, so that in the embraced region only a verysmall gap remains between the rolling body and the cage pocket, and therolling bodies can therefore be guided so at closely tolerancedspacings.

Further advantages are gained by having the concavely curved regionfollow approximately a semicircle or a smaller segment of a circle. Thismakes it possible to introduce the balls into the pocket from its openside, particularly after the rolling bearing is assembled, for examplethrough a filling channel.

The subsequent filling of the cage with rolling bodies is alsofacilitated particularly by the fact that after the cage is placed inthe groove provided for it, the radius of the concavely curved region inthe area, particularly the plane, of the spine region of the cage isequal to or greater than the equatorial radius of curvature of therolling body received in the pocket concerned. The rolling bodies canthus be introduced without any risk of jamming.

The invention is suited in particular for rolling bearings whose rollingbodies have a doubly curved, particularly doubly convexly curved, jacketsurface or outer surface, preferably for spherical rolling bodies,particularly in the context of a four-point bearing.

Within the scope of a preferred embodiment, it can further be providedthat the inner face of at least one pocket for receiving a respectiverolling body has at least regionally a double concave curvature, i.e.,is concavely curved in two mutually perpendicular directions. Sphericalrolling bodies, in particular, can thus be embraced over a substantialarea, making it possible to align the rolling bodies at uniform spacingwith the least possible surface pressure, thus eliminating localoverloading of the cage.

This aspect of the invention can be further enhanced in that the doublyconcavely curved region of a pocket approximately follows the surface ofa hemisphere or two spaced-apart quarter spheres, or follows one or twosmaller segment(s) of a hollow sphere. A compromise is thereby reachedbetween maximum encapsulation of a spherical rolling body and a largeenough opening so that the balls can be subsequently introduced.

It follows from this that one or preferably both, depending on thedirection of rotation of the rolling bearing front or back sides*, of aspacer each follow a segment of the surface of a hollow sphere,preferably each approximately one fourth of the surface of a hollowsphere or a smaller portion thereof. Assuming that the pockets receivingthe rolling bodies are symmetrical to a vertical plane extendingcentrally between two spacers, this results in an arrangement in which aspacer has two mutually symmetrical, doubly concavely curved flanks onits front side and back side, referred to the particular direction ofrotation.

A rolling bearing arrangement according to the invention can, by allmeans, have two or more mutually offset rows of rolling bodies, theoffset being in the axial direction of the bearing. Under thesecircumstances, cages according to the invention are preferably insertedin all the rows of rolling bodies.

One, more or all of the rows of rolling bodies can be fashioned in themanner of a four-point ball bearing, particularly in the manner of apreloaded four-point ball bearing. A cage according to the invention iscapable of applying the forces needed to align such preloaded rollingbodies without deformation.

The invention further provides that the gap between the two rings issealed at one or preferably both end faces of the rolling bearing tokeep out foreign bodies that might damage the raceways, the balls and/orthe cage.

Sealing at both ends also makes it possible for the gap between the tworings, particularly within the two end-face seals, to be filled with alubricant, particularly with grease. Since the grease cannot leak out,the regreasing interval can be chosen to be very long, which isespecially advantageous precisely in the case of wind turbines,including, under some circumstances, in the offshore environment.

Further advantages are afforded by providing, in one annular connectingelement, a filling channel that extends from one end face or jacket sideto the raceway and serves to introduce rolling bodies, particularlyballs. It has proven particularly effective to dispose the fillingchannel in an annular connecting element that does not have a groove forreceiving the cage spine, so that the rolling bodies can be introducedinto a pocket of the cage from the open side. Such a filling channel canpreferably open into a connecting-element jacket surface that faces thegap, so that it can extend in a straight line, i.e., parallel to thebase plane of the bearing.

Furthermore, one or preferably both annular connecting elements comprisecoronally distributed fastening means for connection to a frame, machinepart or system part, preferably coronally distributed boresperpendicular to an end face. Such an arrangement is the only way toensure that the often high forces that occur between themounted-together system components will be safely absorbed by a bearingaccording to the invention.

The invention can be developed further by providing at least one of theannular connecting elements with a continuously circumferential row ofteeth, particularly on a jacket surface disposed oppositely from thegap. At such a continuously circumferential row of teeth, torques can beintroduced into or tapped from the rotary joint, for example todeliberately move to a given angle of rotation and/or to keep the anglestable, and/or to drive the rotary joint.

The invention further provides a rotary drive, particularly one or moreelectric or hydraulic motors, for rotationally adjusting the two annularconnecting elements relative to each other.

Such a rotary drive can, in this application, be coupled to a connectingelement via a (respective) pinion, toothed wheel, worm or the likemeshing with a continuously circumferential row of teeth of thatconnecting element, and can be affixed to the other annular connectingelement or to a housing part or frame part attached thereto.

A rolling bearing according to the invention preferably findsapplication as a rotor bearing or main bearing of a wind turbine,and/or—particularly in the form of a rotary drive with an inwardly oroutwardly toothed connecting ring—as a blade bearing of a wind turbine,and/or as a nacelle bearing of a wind turbine.

A wind turbine according to the invention is distinguished by a rotorbearing or main bearing configured according to the criteria articulatedabove, and/or by at least one blade bearing so constructed, and/or by alike-constructed nacelle bearing.

Further features, details, advantages and effects based on the inventionwill become apparent from the following description of a preferredembodiment of the invention and by reference to the drawing. Therein:

FIG. 1 is a cross section through the rings of a rolling bearingaccording to the invention;

FIG. 2 is perspective partial cutaway view of the outer ring of therolling bearing from FIG. 1, together with a cage guided therein, havinga plurality of pockets each provided to receive a respective rollingbody, a rolling body being placed in one pocket by way of example;

FIG. 3 shows the cage of the rolling bearing from FIGS. 1 and 2 inperspective view and largely straightened out;

FIG. 4 is an enlarged representation of a detail from FIG. 2; and

FIG. 5 is a perspective representation of a cage according to anotherembodiment of the invention.

The rolling bearing 1 depicted by way of example in the drawing servesto rotatably connect a first system part or machine part to a foundationor to a second system part or machine part. For this purpose, therolling bearing 1 is provided with two annular connecting elements 2, 3.

The section through the rolling bearing 1 illustrated in FIG. 1 revealsits internal construction. The typical structure of a radial bearing isevident, in which a first connecting element 2 is configured as a flatouter ring, which can be seen on the left in FIG. 1, while the secondconnecting element 3 is configured as an inner ring 3, on the right inFIG. 1, that is disposed concentrically inside the outer ring 2. The twoconnecting elements 2, 3 each have an approximately rectangular crosssection. Between the inner jacket surface 4 of the outer connectingelement 2 and the outer jacket surface 5 of the inner connecting element3 there is a narrow gap 6 that runs approximately vertically and has aconstant, very small width, such that the two connecting elements 2, 3are rotatable in opposite directions about an axis that is at the centerof the rings 2, 3 and perpendicular to the base plane of the bearing.

During such relative rotation, the two connecting elements 2, 3 are keptoriented exactly concentrically with each other by a multiplicity ofrolling bodies 7 disposed in the gap 6 between the two connectingelements. These rolling bodies 7 each have a spherical shape and rollbetween two raceways 8, 9, one 8 disposed in the inner jacket surface 4of the outer connecting element 2, and the other 9 in the outer jacketsurface 5 of the inner connecting element 3.

Each of the two raceways 8, 9 has a cross section that is approximatelysemicircular but nevertheless differs minimally from the ball crosssection; for example, the radius of the raceway cross section can beminimally larger than the radius of the ball cross section.

In the manner of a single-row four-point bearing, each rolling body 7thus always has two nearly punctiform areas of contact with each of thetwo raceways 8, 9; these contact areas are always at an angle of ±45° toeach other, viewed from the center of a spherical rolling body 7, butcan shift in various directions when the rolling bearing 1 is underload.

The bearing is also preferably preloaded, i.e., play-free. The sphericalrolling bodies 7 and/or the raceways 8, 9 are each minimally elasticallydeformed by this process.

In addition, the gap 6 is closed by a respective seal 12, 13 in theregion of its debouchment at each of the two end faces 10, 11 of thebearing. The gap 6 thus sealed to the outside is filled with alubricant, particularly with grease.

As can further be appreciated from FIG. 1, each of the two annularconnecting elements 2, 3 comprises a relatively large number ofcoronally distributed fastening means, particularly in the form offastening bores 14, 15, which optionally can be implemented as blindbores sunk from one bearing end face 10, 11 and/or as through-borespassing all the way through the particular connecting element 2, 3between its two bearing end faces 10, 11, as illustrated in FIG. 1. Suchfastening bores 14, 15 are used to screw in or push through machinescrews that are simultaneously anchored to a machine part or systempart.

In addition, one of those two jacket surfaces 16, 17 of the twoconnecting elements 2, 3 which face away from the gap 6 can be providedwith teeth, with which a, for example, driven pinion, toothed wheel,worm or the like can be brought into engagement, while the housing ofsuch a drive would preferably be fixable to the respective otherconnecting element 2, 3.

Roughly equidistant positions of the rolling bodies 7 along the raceways8, 9 are kept as constant as possible by a cage 18, which is illustratedin isolation in FIG. 3.

Such a cage 18 preferably consists of a spring-elastic material, forexample of spring steel, and can thus be bent without damage and withoutresidual deformation.

It is, moreover, interrupted in at least one location and therefore hasthe shape of a strip with two ends 19, 20, i.e., is not endless. Owingto these two measures, the cage 18 need not be pre-bent to the racewaydiameter of the rolling bearing 1, but can, where appropriate, befabricated as a straight-extending part, particularly stamped orlaser-cut from a (metal) sheet or (metal) strip. The cage could also bepre-bent to a standardized curvature and would still be usable for alarge number of rolling bearings 1 irrespective of their exact racewaydiameters; for this purpose, it could also be shortened by a givenamount as needed.

FIG. 3 is a schematic construction diagram of the cage 18: the latterhas the shape of a flat strip in which regularly recurring recesses 23,24 are cut into both narrow longitudinal sides 21, 22, which, forexample, were originally straight or extended concentrically with acommon center.

Cut into longitudinal side 21 are larger recesses 23 having anapproximately semicircular base area, whose radius is approximatelyequal to or minimally greater than the radius of a ball 7; theserecesses 23 serve as pockets, each receiving a respective sphericalrolling body 7.

Smaller recesses 24 are cut into the opposite longitudinal side 22;these notches 24 serve to locally reduce the stiffness of the cage 18,and can serve as designated bending areas if necessary.

The notches 24 are preferably each located on the line of symmetrybetween a respective two adjacent pocket recesses 23. Since thecenter-to-center distance between pocket recesses 23 is (slightly)larger than the width of a pocket recess 23, a projection remains righton the line of symmetry between two adjacent pocket recesses 23 andserves as the spacer 25 between two adjacent rolling bodies 7, to keepthem from coming into direct contact and to ensure instead that thespacing between them remains the same. The free end face of such aspacer 25 can be rounded and/or have rounded edges.

Since the cage strip 18 is wider than the depth of a pocket recess 23,and thus is preferably wider than the radius of a ball 7 receivedtherein, and is also wider than the depth of a notch 24, the spacers 25are simply connected on the longitudinal side 22 facing the pockets 23;the result is a comb-like structure, with the tines of the combcorresponding to the spacers 25 and the comb spine or cage spine 26corresponding to the region of the cage near its longitudinal side 22,which is incised only slightly by the notches 24.

The cage 18 is not bent like a cylinder jacket, according to the usualpractice, and inserted in the gap 6 of the rolling bearing 1; instead,the cage spine 26 is bent in a plane in the manner of an annular diskand is placed in a circumferential groove 27 machined into a raceway 8,9—in the illustrated case, in raceway 8 of the radially outer connectingelement 2. Since this groove 27 is located (approximately) at half theheight of the raceway 8 and thus divides the latter into two(approximately) equal large halves of approximatelyquarter-circle-shaped cross section, the flat cage 18 placed thereinextends to the height of the centers of the spherical rolling bodies 7.The free ends of the spacers 25 lie approximately on a circular linethat passes simultaneously through the centers of all the sphericalrolling bodies 7.

To enable the cage 18 to be bent easily into a circle corresponding tothe particular gap diameter or raceway diameter, a notch 24 is providedacross from each spacer body 25, on the line of symmetry thereof. Thedepth of each notch 24 approximately corresponds to the minimum width ofthe cage spine 26 in the region of the base of a pocket 23, or can evenbe greater than said width. The notches 24 can have an approximatelyV-shaped base surface, preferably with rounded edges in the region ofthe notch base and at the two regions of transition to the approximatelystraight longitudinal side 22 of the cage 8.

A notch 24 can be shaped so that a section through the cage 18 takenfrom the base of a notch 24 and/or from the thereto-adjacent region of aflank of the notch 24 and extending approximately radially with respectto the center of the adjacent pocket 23 has a relatively small crosssection or even the smallest cross section of the cage 18, so that thelatter has a tendency to bend at those locations as needed, owing to theweakness of the material there.

Even if, after bending has taken place there, residual deformation stillremains as a result of local overloading, this would still have littleimpact on the ability of the inventive cage 18 to function, since therespective base areas of the adjacent pockets 23 would be changed verylittle by this and a rolling body 7 received in them thus would notbecome jammed.

FIG. 5 illustrates another embodiment of a cage 28 according to theinvention.

Cage 28 differs from the previously described cage 18 primarily in theshape of the spacers 29, whereas the cage spine 30 that is to be placedin the groove 27 is identical to the cage spine 26 of cage 18. Ahorizontal longitudinal section along the main central plane of the cage28 is also identical to a corresponding longitudinal section throughcage 18.

In contrast to cage 18, however, cage 28 does not have a flat shape witha constant thickness, but rather, the spacers 28 additionally extend inthe third dimension, upward and downward out of the plane of the cagespine 30.

Each spacer 29 is essentially bounded by five surfaces and is formedtogether with the cage spine 30 on the remaining side.

Correspondingly to the transverse curvature of the raceway 8, the topface 31 and the bottom face 32 of a spacer 28 have a curvature that iscomplementary thereto, so that they are able to slide in the raceway 8with as little friction as possible. To this end, the transversecurvature diameter of the spacers 28 can be slightly smaller than thetransverse curvature radius of the raceway 8. Where applicable, the topface 31 and the bottom face 32 can also have a slight curvature in thelongitudinal direction of the cage 18, approximately corresponding tothe longitudinal curvature of the raceway 8.

From the cage spine 30 outward, the top face 31 and the bottom face 32diverge from each other to an end face 33 that joins the free edges ofthe two surfaces 31, 32. This end face 33 follows approximately thecourse of the gap 6 above and below the raceway 8; it can be flat orslightly curved in the manner of a cylinder jacket surface,correspondingly to the cylindrically curved course of the gap 6.

The two surfaces 35, 36 adjacent the neighboring pockets 34 of a spacer28 each follow a segment of the surface of a hollow sphere; they formthe counterpart to the spherical rolling bodies 7 received in thesepockets 34, and are curved with approximately the same radius as theyare, but concavely rather than convexly. These surfaces 35, 36 taper inthe direction of the pocket 34 down to the cross section of the cagespine 30. However, they preferably continue thereinto without a step orbend, i.e., continuously and differentiably, preferably in the form of aportion of the surface of a cylinder jacket or hollow sphere.

The two mutually facing pocket boundary surfaces 35, 36 of neighboringspacers 28 could also pass directly into each other, especially if thepockets 34 do not extend into the groove 27, i.e., if their depth isequal to the width of the cage 28 minus the depth of the groove 27.Nevertheless, a gap of approximately constant width and extendingapproximately to the plane of the cage spine 30 should still remainbetween the facing pocket boundary surfaces 35, 36, so that the rollingbody 7 received in the pocket 34 concerned has enough free space to formareal regions of contact with the raceway 8. Consequently, the area ofeach pocket boundary surface 35, 36 is preferably slightly less than onefourth the area of a hollow sphere.

Although in the illustrated embodiment the groove 27 is provided in theradially outwardly disposed connecting element 2, it could just as wellbe located in the radially inwardly disposed connecting element 3. Thelongitudinal side 22 of the cage 18, 28 that runs along the cage spine26, 30 would then be concavely rather than convexly curved.

To fill the pockets 23, 34 after the connecting elements 2, 3 have beenassembled, there is provided at least one sealable filling channel whosecross section is at least equal to the cross section of a sphericalrolling body 7. Such a filling channel is preferably provided in theparticular connecting element 2, 3 that does not have a groove 27; itbegins at the raceway 8, 9 there and debouches in a surface region ofthat connecting element 2, 3 outside the gap 6, particularly beyond thetwo seals 12, 13, preferably at a jacket surface 16, 17 facing away fromthe gap 6. Should one of these two jacket surfaces 16, 17 be providedwith continuously circumferential teeth, for example for coupling arotary drive, then it is advisable to place the groove 27 in this sametoothed connecting element 2, 3, whereas the fill opening(s) should beprovided in the respective other, untoothed connecting element 2, 3.

Thanks to the cage 18, 28, the rolling bodies 7 of the rolling bearing 1are always guided at approximately equidistant relative positions, evenunder heavy loads. Rolling bearings 1 equipped with such cages 18, 28can therefore also be operated in the preloaded state, the sphericalrolling bodies 7 always being loaded in compression. Suchhigh-load-capacity rolling bearings 1 are especially suitable for windturbines, where they can be used as blade bearings, main rotor bearingsand nacelle bearings.

List of Reference Numerals 1 Rolling bearing 2 Outer ring 3 Inner ring 4Inner jacket surface 5 Outer jacket surface 6 Gap 7 Rolling body 8Raceway 9 Raceway 10 Bearing end face 11 Bearing end face 12 Seal 13Seal 14 Fastening bore 15 Fastening bore 16 Jacket surface 17 Jacketsurface 18 Cage 19 End 20 End 21 Longitudinal side 22 Longitudinal side23 Pocket recess 24 Notch 25 Spacer 26 Cage spine 27 Groove 28 Cage 29Spacer 30 Cage spine 31 Top face 32 Bottom face 33 End face 34 Pocket 35Pocket boundary surface 36 Pocket boundary surface

1. A rolling bearing assembly for a main blade or nacelle bearing of awind turbine, the assembly comprising two annular connecting elements(2, 3) arranged concentrically to each other and at least regionally oneinside the other, and forming a gap (6) between said connecting elements(2, 3), the connecting elements being rotatable in opposite directionsabout an axis at the center of said connecting elements (2, 3) andgenerally perpendicular to a ring plane, wherein at least one raceway(8, 9) is provided for at least one row of rotationally symmetricalrolling bodies (7) rolling between said connecting elements (2, 3) inthe region of the gap surrounding the axis of rotation at a generallyconstant radius, wherein the said rolling bodies (7) of one row areguided at approximately equal spacings by a cage (18, 28) having atleast one disk-shaped region that is placed in a continuouslycircumferential, groove-shaped depression (27) in the region of saidraceway (8, 9) of one said connecting element (2, 3), and wherein saidcage (18, 28) comprises a plurality of spacers (25, 29) that areconnected to a spine (26, 30), and disposed between every twoneighboring spacers (25, 29) is a recess (23, 34) for receiving thespherical rolling bodies (7), wherein the opening of a recess (23, 34)extends continuously in a top face of said cage (18, 28), over theopposite edge (21) thereof from said spine (26, 30) and into the bottomface thereof, wherein said cage (18, 28) is interrupted in at least onelocation and is formed from a spring-elastic material, such that it canbe elastically bent open and closed in the plane of the disk-shapedregion.
 2. The rolling bearing assembly as in claim 1, wherein said cage(18, 28) is of steel.
 3. The rolling bearing assembly as in claim 1,wherein said spacers (25, 29) of said cage (18, 28) are connected to oneanother, such that said recesses (23, 34) are connected to one another.4. The rolling bearing assembly as in claim 3, wherein when a distancebetween end faces (33) of the two neighboring spacers (25, 29) changes,the end faces (33) top and bottom edges do not shift in relation to eachother.
 5. The rolling bearing assembly as in claim 1, wherein said cage(18, 28) consists of only one layer.
 6. The rolling bearing assembly asin claim 1, wherein at least one of said spacers (25, 29) has a greaterheight than said spine (26, 30) of said cage (18, 28).
 7. The rollingbearing assembly as in claim 1, wherein all of said recesses (23, 34) ofsaid cage (18, 28) are open on the opposite longitudinal edge (21) ofsaid cage (18, 28) from said spine (26, 30).
 8. The rolling bearingassembly as in claim 1, wherein said cage (18, 28) has at least onedesignated bending area in the spine region thereof.
 9. The rollingbearing assembly as in claim 1, wherein at least one bending areaextends transversely to the circumferential depression of said rollingbearing (1).
 10. The rolling bearing assembly as in claim 9, wherein atleast one bending area is located in a region of a spacer (25, 29). 11.The rolling bearing assembly as in claim 9, wherein at least one bendingarea is configured as a recess (24) in said cage (18, 28), in an endface (22) of said spine (26, 30).
 12. The rolling bearing assembly as inclaim 11, wherein the maximum depth of said recess (24) approximatelycorresponds to a minimum width of said spine (26, 30) at a base of saidrecess (23, 34).
 13. The rolling bearing assembly as in claim 11,wherein said recess (24) passes through said spine region of said cage(18, 28) from the top face thereof to the bottom face thereof.
 14. Therolling bearing assembly as in claim 11, wherein at least one saidrecess (24) has rounded edges extending vertically in relation to thebase of said rolling bearing (1), in the region of the transitionbetween flanks of said recess (24) and/or beyond the two flanks of saidrecess.
 15. The rolling bearing assembly as in claim 1, wherein saidrolling bodies (7) are embraced by said cage (18, 28) where theperipheral speed of said rolling bodies is highest, hence generally inthe regions of their equators.
 16. The rolling bearing assembly as inclaims 1, wherein said rolling bodies (7) are embraced over no more thanabout 180° of their circumferences.
 17. The rolling bearing assembly asin claims 1, wherein an inner face of at least one of said recesses forreceiving a respective rolling body (7) is at least regionally provided,generally at the level of said spine (26, 30) of said cage (18, 28),with a concave curvature.
 18. The rolling bearing assembly as in claim17, wherein said concavely curved region follows generally a semicircleor a smaller segment of a circle.
 19. The rolling bearing assembly as inclaims 17, wherein after said cage (18, 28) is placed in the depression(27) provided therefor, the radius of the concavely curved region in thearea of said spine (26, 30) of said cage (18, 28) is equal to, orgreater than, the equatorial radius of curvature of the said rollingbody (7) received in the respective recess.
 20. The rolling bearingassembly as in claim 1, wherein said rolling bodies (7) have a doublyconvexly curved outer surface.
 21. The rolling bearing assembly as inclaim 20, wherein said rolling bodies (7) comprise balls.
 22. Therolling bearing assembly as in claim 1, wherein an inner face of atleast one said recess for receiving a respective rolling body (7) has atleast regionally a double concave curvature, i.e., is concavely curvedin two mutually perpendicular directions.
 23. The rolling bearingassembly as in claim 22, wherein the doubly concavely curved region of asaid recess follows approximately a selected one of the surface of ahemisphere, or two spaced-apart quarter-spheres, or one or two smallersurface segment(s) of a hollow sphere.
 24. The rolling bearing assemblyas in claim 23, wherein depending on the direction of rotation of saidrolling bearing (1), front or back sides (35, 36) of a spacer (25, 29)each follow a segment of a surface of a hollow sphere, each generallyone fourth or less of the surface of a hollow sphere.
 25. The rollingbearing assembly as in accordance with claim 1, wherein the rollingbodies comprise two or more mutually offset rows of rolling bodies (7),the offset being in the axial direction of said rolling bearing assembly(1).
 26. The rolling bearing assembly as in claim 1, wherein one, moreor all of the rows of said rolling bodies (7) and their raceways (8, 9)are fashioned in the manner of a preloaded four-point ball bearing. 27.The rolling bearing assembly as in claim 1, wherein said gap (6) betweensaid connecting elements (2, 3) is sealed at both end faces (10, 11) ofsaid rolling bearing (1).
 28. The rolling bearing assembly as in oneclaim 27, wherein said gap (6) between said connecting elements (2, 3),within two end-face seals (12, 13), is filled with grease.
 29. Therolling bearing assembly as in claim 27, wherein a filling channelextending from one end face or jacket surface (10, 11, 16, 17) to saidraceway (8, 9) and serving to introduce the rolling bodies (7), isprovided in one of said annular connecting elements (2, 3), that doesnot have a groove depression (27) for receiving said cage spine (26,30).
 30. The rolling bearing assembly as in claim 29, wherein both ofsaid annular connecting elements (2, 3) comprise coronally distributedfastening means for connection to a frame, machine part or system part,the fastening means comprising coronally distributed bores (14, 15)perpendicular to an end face (10, 11).
 31. The rolling bearing assemblyas in claim 1, wherein at least one of said annular connecting elements(2, 3) has a continuously circumferential row of teeth on a jacketsurface (16, 17) disposed oppositely from the gap (6).
 32. The rollingbearing assembly as in claim 31, wherein said continuouslycircumferential row of teeth is provided on the annular connectingelements that has a depression (27) in which said cage spine is to beplaced.
 33. The rolling bearing assembly as in claim 1, and furthercomprising an electric motor for rotationally adjusting said two annularconnecting elements (2, 3) relative to each other.
 34. The rollingbearing assembly as in claim 32, wherein a rotary drive is coupled toone of said annular connecting elements (2, 3) via a pinion or toothedwheel or worm, or the like meshing with a continuously circumferentialrow of teeth, and is affixed to the other of said annular connectingelements (2, 3).
 35. A wind turbine in combination with a rotor bearingor main bearing (1) configured according to claim
 1. 36. A wind turbine,in combination with a blade bearing (1) configured according to claim 1.37. A wind turbine, in combination with a nacelle bearing (1) configuredaccording to claim 1.